Medical About sexual urge

When young people suddenly see something that sexually hit them on, e.g a nude person on magazines, television,...even in the street.
What happens inside their body i.e hormones most secreted ?
Do those hormones exist in animal, like in a mouse, also ?
Thanks

I'm going to give a rather vague answer tonight (because it's nearly my bedtime), which is that a LOT of things happen, and it's not really a straightforward, easy answer. It also depends on which sex you're talking about. And, while there are species differences in responses, there are also many similarities across species as well.

Is there something more specific you had in mind that prompted this question that can help focus an answer? We teach entire courses on this subject, so you're asking a lot for a discussion forum response.

Thanks MoonBear,
I find young people often get excited if they see their sex partners or their loved sexes undressing. There must be something inside near the belly button secreted and unbeathable moments, then there might be sighing of relax. I'd like to know if mice secret something similar too if they meets their lover, not until they have sexual intercourse.

Ha, no, nothing near the belly button. Believe it or not, most of the reaction happens at the level of the brain. But, yes, in all mammals, arousal occurs prior to actual mating...it's rather a necessity. Mice are not monogamous at all, so any partner will generally do. Humans are a bit more discriminating.